GuoJun -
Perhaps I don't understand your use of 'algorithm'. I'm not a math person, only a fractal designer. How is this picture a fractal? I'm asking because I really don't know. It just doesn't look like any 'fractal' I've seen, so I don't understand it.
...................Patrice

Thank you Patrice for your comment and I have never see other artist creating things like this using algorithms, the most likely style is fractal art.
For this one i should saw the tree is fractal really, i am trying something new i think, and until now i know algorithm art is looks like fractal art.